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About dkirk
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  1. dkirk

    Vivitar 2000

    I have had some burnt reflectors on Vivitar slave flash units before, and I just line them with aluminum foil to make the surface a pretty decent reflector again. Probably not as good as a brand new reflector, but they seem to work just fine for me. Just FYI, Don
  2. dkirk

    Eneloop 1500s?

    SnwbrdrRm, The Tenergy 2500 mAh batteries are not "low self discharge" NiMH batteries, whereas the Eneloops are in the "low self discharge" class of NiMH batteriers. "low self discharge" NiMH batteries are also marketed as "pre-charged" or "ready to use" because they can be charged at the factory and will retain their charge for a long time (typically retain 60 to 70% of their charge after one year), whereas standard NiMH batteries self discharge at an approximate rate of 30% per month after they have been charged. Example : a standard 2500 mAh battery that is charged but not used for 4 weeks after it has been charged will only have 1750 mAh available, whereas a 2000 mAh low self discharge battery will have approximately 1900 mAh available after one month. Therefore if you want to put a trail camera out in the field for a long time (like over a month), then low self discharge batteries that only have a capacity of 2000 mAh will often provide longer run time than standard 2500 or 2700 mAh NiMH batteries due to the self discharge issue. I would say the decision point is about 3 weeks. If you put a trail cam out but only leave them out for 3 weeks or less, then standard NiMH batteries might be a good choice, but if you intend to leave your trail camera out in the field longer than 3 weeks you should consider low self discharge batteries like the Eneloop. Don
  3. dkirk

    Mosfet Question

    One more comment. If need to make sure that your amp/mic hardware is not connected to the AIO board common. If it is connected to the AIO board common, then your amp/mic hardware will be on all the time. Don
  4. dkirk

    Mosfet Question

    Hello HunterTom, Thanks for the sketch. I assume you are trying to power your amp/mic using the battery that is feeding the AIO board based on how you show it in your sketch (please confirm), and if this is the case the spare mosfet which is a 2N7000 can only handle 200 mA of current. Any idea how much current your amp and mic draw? Don
  5. dkirk

    Mosfet Question

    I suggest you sketch and post your circuit (what and how you are connecting the wires from your external devices to the AIO board), and this might help us provide some troubleshooting ideas. Don
  6. dkirk

    Best Way To Drain Flash Capacitor?

    Any size wire will work. I typically just use solid conductor telephone wire which is 24 gauge. Don
  7. dkirk

    Mosfet Question

    In general a shorted mosfet (drain to source) is a very common failure mode (but I personally have never had a failed mosfet on the AIO board). Also please note that most Mosfets have an internal diode across their output (between the source and drain), and if you connect your wires up to the Mosfet backwards (with the incorrect polarity) the diode will conduct (look like the Mosfet is on all the time) and it can also draw too much current depending on the external circuit which would then cause possible Mosfet failure. Both types of Mosfets used on the AIO board do have the internal diode mentioned above. (double check your soldering to make sure you don't have a solder bridge) Don
  8. dkirk

    Bf Outdoors

    Chris (212) and Dave (Treetop), Excellent news, and thanks for doing this for the home brew community. Don
  9. dkirk

    Best Way To Drain Flash Capacitor?

    I use a 100 ohm 10 watt resistor available at radio shack. They sell a package of two for $2.19, and the part number is 271-135. Just solder a insulated wire to each leg of the resistor, and then you can use the ends of the wires to discharge the capacitor. You will likely see a faint spark when you touch the wires to the capacitor if the capacitor was fully charged (which is something I actually like to see because I know I was successful in making contact). The 100 ohm resistor is a great value to use because it will quickly discharge the capacitor (in less than one second). Never hurts to measure the voltage on the capacitor using a DC volt meter after you have attempted to discharge charge in order to make sure you were successful (as Ken mentioned above). Don
  10. dkirk

    Testing A503 Hack

    Deleted, please read other posts above.
  11. dkirk

    Vivitar 2800 Question- Dkirk Help !

    firemanjim, Yep, as tree sight said, that is the trigger transformer. Normally you can just solder that wire back on unless the lead on the top of the transformer has completely broken off. This transformer generates an approximate 4500 volt pulse which causes a small spark within the flash tube and this small spark is what causes the flash tube to fully conduct and dump all the energy stored in the flash capacitor into the flash tube. Trigger transformers are very common (and pretty generic), and you should be able to buy another one to replace your broken one (just have to figure out what wires go where and you need enough space to accommodate the new one). Sometimes they will have 3 wires, and sometimes 4 wires, but both styles will work (if it has 4 wires, two of the wires need to be connected together). You can search "trigger transformer" on e-bay, and you will find numerous ones available, but much cheaper if you have a bad flash unit that you can salvage the trigger transformer from. Here is an E-bay example that would work fine http://cgi.ebay.com/Trigger-coil-transform...=item19c23d485c Don
  12. dkirk

    Slave Controller Test Results

    Internal resistance is typically related to cell size, and therefore a 6 volt open circuit voltage measurement on AA batteries does not mean it will perform similar to C or D cells that also have a 6 volt open circuit value. Depending on the logic and the conditions of the battery, it's possible that AA batteries may experience excess voltage drop that can cause automatic resets of the processor, etc, whereas the C or D batteries will experience less voltage drop due to their lower internal resistance and this might prevent automatic resets (it just all depends on the circumstances). The importance of internal battery resistance is most noticeable when pulling very high current (when charging up a slave flash that has been discharged, etc.). Also be aware that cold temperatures will cause the internal battery resistance to greatly increase, so even if the device is working properly at room temperature, don't be totally surprised if problems crop up when it gets cold. When designing trail cam circuits I recommend freezer testing the design using the style of batteries you intend to use in order to make sure the device still operates properly. Also note that there is a large difference in internal resistance value based on the battery chemistry. Alkaline batteries have considerably higher internal resistance compared with Ni-Cad and NiMH batteries as an example. Note : Internal battery resistance also increases as the battery energy is depleted. Just FYI, Don
  13. dkirk

    Viv 3700 Wiring Issue

    If all else fails, you can wrap the end of the trigger wire around the strobe tube where it normally is attached onto the tube, and then solder it (the trigger wire) onto itself. The trigger wire sets up a strong electric field which causes ionization within the tube which then causes it to conduct, but typically the trigger wire is external (does not go inside the tube), and this is why you can typically just wrap it around the tube if needed. Don
  14. dkirk

    Need Opto Help

    Gary, You will notice the the current transfer ratio for the first IC in the list is evaluated at 10 ma, while the second IC in the list is evaluated at 1 ma, and therefore not really comparing apples to apples (it's very possible that their CTR is similar if not identical if you look at the actual datasheet for the two devices (take a look at the datasheet parameter section as well as the Output Current Vs. Input Current Curve for each device). I see some of the Fairchild devices list the current transfer ratio at LED input currents of both 10mA and 1mA, while others only list the value at the 10 mA level. The current transfer ratio is really gain of the device (Transistor output current divided by LED input current) x 100, and a higher CTR allows you to use less current to drive the LED to turn on the output transistor which can be advantageous when trying to conserve energy. You really did not mention how you are using the device, but likely you will not have any problems (as Rick mentioned above). Don
  15. A 5 watt rating means it can handle higher current without being destroyed compared with a 2 watt rating, but typically a higher wattage rating also means that the resistor is physically larger in size. Therefore you can use a 5 watt or a 10 watt resistor (as an example) in place of a 2 watt resistor without any problems as long as you have available space. Don